Yes, but not in the way you started out doing.
Your mother owns the home, and isn't interested in having live in help.
Furthermore, she isn't kind to the girl, so getting her a place there won't make her life anymore pleasant. All that would do if you were even successful, would be to make her beholden to someone who already looks down upon her. That's a recipe for abuse.
Help her find an agency or a listing service where she *can* find a live-in position. You can write her a reference, since you are familiar with her work. What she needs is an opportunity to succeed on her own, handouts are temporary. She needs extra food too, but as much as anything, she needs a better job- one that will provide her with a room and a way to eat.
You could check at the local Council on Aging and see if they have any clients who need help, or search the local papers, or check with local real estate agents- they generally know everyone's business. Chances are good, they will respond better to you than they would if she inquired on her own. If you are willing to advocate for her, you can probably find her a better situation. You're doing the right thing. How sad that your mother cannot.
Also, check with the local churches, especially the Universalist Unitarians- they will help her as well.